I eventually found the problem!
It felt so weird to me that even my backups and autosaves were now crashing with the same issue. The structs needing to be refreshed was a seperate problem that was simply there because due to a different problem they could not be resolved.
The real problem was I had decided to reinstall/verify 5.6.0 as it was feeling a little buggy, in doing so it reset my macro libraries where I had created additional Macros like ForLoopWithDelay and ForEachLoopWithDelay. With these missing I could not open the problem blueprints as it would immediately crash.
I found this out by copying blueprints over to a new project, there I could open them and actually see the blank MacroInstance nodes, just had to remake those macros and replace to get it working again 